(1) Field of the Invention
The present invention is directed to tow cables for use with surface ships and underwater vehicles. In particular, the present invention is directed to integrating transduction material into the coaxial cable component of a tow cable for use as an acoustic transducer, taking advantage of the cable's long length to achieve significant acoustic source level.
(2) Description of the Prior Art
Surface ships and underwater vehicles often use tow cables while towing arrays of equipment such as hydrophones. Coaxial cables are commonly integrated into tow cables to transmit power and data to the tow body. Prior art tow cables and tow bodies adapted for use with ships and underwater vehicles require a large handling system, a dedicated room, and a stern door. Mechanical problems plague the deployment and retrieval efforts. Furthermore, a heavy tow body leads to a steep critical angle for the tow cable, requiring fairing and a specialized winch with multiple drums. The winch (and foundation) rating must exceed the cable breaking strength for safety. In light of some of the implementation problems described above, several “soft tow” concepts have been proposed, replacing an acoustic source in a tow body with a distributed acoustic source in a towed hose wound directly on a winch in an attempt to reduce handling complexity and increase vertical aperture. An acoustic source integrated into the tow cable will impact the handling system minimally. Currently, there is a need for a new type of acoustic transduction device, one integrated directly into a tow cable by replacing the insulating spacer in a coaxial cable with transduction material for use in an armored tow cable, or a dipping sonar cable.